Method of making a three-dimensional sheet puzzle

ABSTRACT

In a three-dimensional sheet puzzle, puzzle pieces fit together to form a shell held by magnetic attraction to a ferromagnetic base. The puzzle pieces are formed from sheet material which lies flat without strain. The shapes of the pieces are slightly distorted when applied to the spherical base. The puzzle is produced by first forming a flexible cover on the base, cutting the cover into pieces, flattening the resulting pieces, cutting pieces from the flexible flat sheet material conforming in shape to the flattened pieces cut from the spherical cover, fitting the pieces of flexible flat sheet material together on the base to recover the spherical base, depicting a puzzle design on the cover formed from the pieces of flexible flat sheet material, laying the pieces of flexible flat sheet material flat again, reproducing the flattened pieces on flexible flat sheet material and cutting out the reproduced pieces from the flat sheet material. In one embodiment, the puzzle is spherical and is another embodiment, the puzzle is curved along two surface dimensions with variation in the radii of curvature and specifically is in the form of a human head.

United States Patent 1191 Myller 1451 Feb. 11, 1975 METHOD OF MAKING A THREE-DIMENSIONAL SHEET PUZZLE Related U.S. Application Data [62] Division of Ser, No. 365,207, May 30, 1973.

[52] U.S. Cl 273/157 R 1511 Int. Cl. A63f 9/12 [58] Field of Search 273/157 R; 35/46 R, 46 A [56] References Cited UNITED STATES PATENTS 2/1963 Stieber et al 35/46 R 11/1971 Barnes 273/157 R Primary Examiner-Anton O. Oechsle Attorney. Agent, or Firm-Lane, Aitken, Dunner & Ziems [5 7] ABSTRACT 1n a three-dimensional sheet puzzle, puzzle pieces fit together to form a shell held by magnetic attraction to a ferromagnetic base. The puzzle pieces are formed from sheet material which lies flat without strain. The shapes of the pieces are slightly distorted when applied to the spherical base. The puzzle is produced by first forming a flexible cover on the base, cutting the cover into pieces, flattening the resulting pieces. cutting pieces from the flexible flat sheet material conforming in shape to the flattened pieces cut from the spherical cover, fitting the pieces of flexible flat sheet material together on the base to recover the spherical base, depicting a puzzle design on the cover formed from the pieces of flexible flat sheet material, laying the pieces of flexible flat sheet material flat again, reproducing the flattened pieces on flexible flat sheet material and cutting out the reproduced pieces from the flat sheet material. In one embodiment, the puzzle is spherical and is another embodiment, the puzzle is curved along two surface dimensions with variation in the radii of curvature and specifically is in the form of a human head.

3 Claims, 13 Drawing Figures METHOD OF MAKING A THREE-DIMENSIONAL SHEET PUZZLE This is a division of application Ser. No. 365,207 filed May 30, 1973.

BACKGROUND OF THE INVENTION This invention relates to sheet puzzles of the jig-saw type and more particularly to a puzzle of the jig-saw type which forms a three-dimensional figure.

Prior to the present invention, a spherical puzzle of the jig-saw type comprising a map of the globe has been proposed in U.S. Pat. No. 3,618,955. In this puzzle, rigid puzzle pieces in the form of a spherical shell are fitted together on a spherical base. The puzzle pieces are provided with permanent magnets to attach them to the spherical base which is made of a material of high permeability. To manufacture this puzzle of the prior art, a spherical cover is formed on the spherical base and a global map is depicted on the spherical cover. The pieces are then cut from the spherical cover and magnets are attached to the puzzle pieces thus formed.

SUMMARY OF THE INVENTION The present invention facilitates the mass production of three-dimensional sheet puzzles and thus enables the cost of manufacture per puzzle to be greatly reduced when a large number of identical puzzles are to be made. In addition, the puzzle of the present invention has greater flexibility in design and is easier to handle and store. These advantages are achieved by making the puzzle pieces flexible and forming them from flat sheet material.

In one embodiment, the puzzle is spherical as in the above described prior art puzzle. In accordance with another aspect of the present invention, the puzzle is made of a different three-dimensional shape. In particular, the base and the puzzle sheet has a surface curved along two surface dimensions, but with a different radii of curvature. This feature enables the puzzle to have many unusual puzzle shapes such as the shape of a human head as in the illustrated embodiment or, for example, in the shape of an egg.

In order to make the puzzle pieces of flat sheet material, a cover of flexible material is formed on the threedimensional base and cut into pieces of the desired puzzle piece shapes. The pieces of the cover are then flattened and pieces having the same shape as the flattened pieces cut from the cover are die cut from flexible flat magnetizable sheet material. The new magnetizable pieces are permanently magnetized and are then fitted together to cover the base. The pieces are held in position by magnetic attraction to the base, which is of ferromagnetic, or in other words, high permeability, material. The puzzle design is then depicted on the cover formed of the magnetized pieces to provide a master set of puzzle pieces. The master set of pieces are then laid flat again and reproduced on additional flexible flat sheets of magnetizable material to mass produce the puzzle pieces, which are subsequently permanently magnetized. The same die used to cut the master set of puzzle pieces is used to cut each reproduced set of puzzle pieces. The reproduced sets of puzzle pieces will fit together on the base to reproduce the original puzzle design.

Because the surface of the base is curved along two surface dimensions, the original pieces cut from the flexible cover are strained and distort slightly when they are flattened. Similarly, the pieces cut from the flat sheet material are strained and distort slightly when they are applied to the base in the opposite direction. As a result, the pieces made from the flat sheet material distort to the same shape as the original pieces cut from the flexible cover. Accordingly, the puzzle pieces will fit together to cover the base even though they are made from flat sheet material.

As pointed out above, the puzzle may be reproduced as many times as desired by the reproduction of the master set of puzzle pieces. In addition, other puzzle designs only require the production of another set of master puzzle pieces, which may be cut with the same die and painted after being applied to the base as described above. Thus, other puzzle designs with the same puzzle piece shape can readily be produced using the same die.

The cutting of the pieces from the original cover of the base and the making of a die to cut corresponding pieces from flat sheet material is required only once for all puzzles having puzzle pieces of the same shapes. Thus, the manufacture and reproduction of the puzzles is facilitated and the cost of manufacturing per puzzle is substantially reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of the three-dimensional puzzle of one embodiment of the present invention;

FIG. 2 is a sectional view through the spherical base of the puzzle illustrating how the base serves as a container for the puzzle pieces;

FIG. 3 illustrates a type of reference mark used on the base of the puzzle to enable the player or players to work simultaneously from different locations on the puzzle design;

FIGS. 4-10 illustrate the process for manufacturing the puzzle pieces;

FIG. 11 is a sectional view taken along lines 11-11 of FIG. 10 illustrating the details of the flexible permanent magnet sheet from which the puzzle pieces are formed;

FIG. 12 illustrates a three-dimensional puzzle of a human head on shoulders; and

FIG. 13 is a sectional view along lines 13-13 of FIG. 12.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in the embodiment of FIG. 1, the puzzle of the present invention employs a ferromagnetic or high permeability spherical base 11 to which puzzle pieces 13 are magnetically attracted and held in place. The puzzle pieces are in sheet form and are flexible. The pieces are of different irregular shapes, the edges of which fit together to form a spherical shell covering and conforming to the curvature of the spherical base 11. When the pieces are fitted together, they provide a spherical ornamental design or picture, which. for example, may be the likeness of a head or a map of the globe. The puzzle pieces are formed from a flat sheet material which is permanently magnetized so as to be able to be magnetically attracted to and held in place by the ferromagnetic base 11.

As shown in FIG. 1, to reduce the difficulty of the puzzle, one of the puzzle pieces 13a may be made larger than the others extending over 180 of a great circle of the sphere to provide a convenient starting point to which additional puzzle pieces can be added when the puzzle is being worked. Alternatively, or in addition thereto, reference markings may be provided on opposite sides of the spherical base 11 and on corresponding puzzle pieces which go on opposite sides of the spherical design to indicate the location of these pieces in the completed design so that a player or players may work simultaneously on different areas on various sides of the sphere. In the case of large spherical puzzles, additional starting points may be marked to permit a player or players to work simultaneously on different areas on the sphere. The reference markings as shown in FIG. 3 may be in the form of an outline of the puzzle piece indicating precisely where the puzzle piece is to be located. Alternatively, the reference puzzle pieces providing starting points may be permanently attached to the sphere.

In the preferred embodiment of the invention, the base 11 is hollow formed in two semi-spheres which fit together with the top half of the sphere underlapping the edge of the bottom half of the sphere to form a container for the pieces 13 as is illustrated in the cross section shown in FIG. 2. The puzzle may be packaged in a box having on the different sides of the box corresponding views of the puzzle to provide a guide for working the puzzle.

When the puzzle pieces have been fitted together on the base 11, the resulting completed puzzle can be supported by a cylindrical pedestal 15 as shown in FIG. 1 to provide a three-dimensional accessory for interior decorating. As shown in FIG. 2, the cylindrical pedestal I5 is hollow and has a supporting web extending across the middle thereof perpendicular to the axis of the cylinder.

The process of manufacturing the puzzle pieces is illustrated in FIGS. 4-10. In order to manufacture the puzzle pieces, a flexible cover 17 is first formed over the spherical base 11, for example, by spraying, as shown in FIG. 4. This flexible cover 17 may be made of latex for example. The cover 17 then is cut into pieces conforming to the desired shape of the puzzle pieces 13 as illustrated in FIG. 5 and removed from the base 11. The pieces of the cover 17 are then flattened on a plane surface 18 as shown in FIG. 6 with the pieces designated by reference number 19 arranged close together, but without overlapping. The pieces 19 are out small enough so that they can be flattened without being substantially strained. In order to prevent substantial straining, each piece needs only to be made small along one spherical surface dimension. For example, the fact the piece 13a extends over 180 of a great circle does not prevent the corresponding piece from being flattened with little strain because the piece is small in the dimension perpendicular to the great circle along which the piece is formed.

After the pieces 19 have been flattened, a die 20 as shown in FIG. 7 is made to cut pieces from flat sheet material conforming to the shape of the flattened pieces 19 shown in FIG. 6. The die 20 is then used to cut a set of pieces from a sheet 21 of flexible magnetizable flat sheet material. The resulting pieces, designated by reference number 22, are then permanently magnetized and fitted together on the base 1 1 as shown in FIG. 8. Because of being permanently magnetized, each piece 22 will adhere to the base 11 and be held in place.

When the pieces 19 are flattened as shown in FIG. 6, the shapes of the pieces will distort slightly. When the pieces 22 of flat sheet material are applied to the base 11, the shapes of the pieces will distort slightly, but in the reverse direction so that they have the same shape on the base II that the pieces 19 had when they were on the base 11. As a result, the pieces 22 will fit together to cover the base 11 even though they were cut from flat sheet material.

After the pieces 22 have been fitted together on the base 11, the desired puzzle design is painted on the resulting cover made of the pieces 22 to thus provide a master set of puzzle pieces as shown in FIG. 8. The resulting master set of puzzle pieces 22 are laid flat on a plane surface in their original arrangement when they were cut out by the die 20. This arrangement of the pieces is readily accomplished by putting the pieces back in the holes in the sheet 21 from which the pieces 22 were originally cut as shown in FIG. 9.

After the master set of pieces 22 have been flattened and arranged, they are reproduced photographically or by color printing techniques as many times as desired on the top surface of an additional flat sheet of flexible magnetizable material. Reproduction may take place directly on the flexible sheet or the reproduction may be carried out on printing paper 24 as shown in FIG. 10 which is then bonded to a flexible sheet 25. After the pieces 22 comprising the master set assembled in a group have been photographically reproduced or printed on the flat sheet 25, the individually reproduced pieces are cut from the sheet 25 by the die 20 to provide the puzzle pieces 13. The pieces 13 are then permanently magnetized so that they will adhere to the base 11. The pieces 13 will fit together on the base 11 to reproduce the design painted on the master set of pieces 22 as described with reference to FIG. 8. The flexible sheet material, such as the sheet 21 from which the master set of pieces are cut or the sheet 25 from the reproduced puzzle pieces 13 are cut, may comprise any suitable elastomer which is impregnated with ferromagnetic material such as powdered red iron oxide used in magnetic recording tape. The sheet material is preferably between one-thirty second and one-sixteenth of an inch thick. As shown in FIG. 11, the opposite side of the sheet 21 from that on which the puzzle design is provided has a protective coating 23 which may include ferromagnetic material dispersed in a suitable flexible bonding material. The ferromagnetic material impregnating the sheet and in the coating is selected to have high magnetic remanence and permanence so that pieces cut from the sheet 21 can be permanently magnetized. The pieces are permanently magnetized on the side thereof with the coating 23 with poles in the form of stripes of alternate polarity.

The pieces 13 and thus the sheet from which they are made must have sufficient flexibility to permit the pieces to conform to the curved surface of the base 11 and be held in contact with the base over the entire surface of each of the pieces by the magnetic attraction between the pieces and the base.

In the puzzle illustrated in FIGS. 12 and 13, the pieces 26 are flexible, permanently magnetized pieces of flat sheet material just like the pieces of the puzzle of FIGS. 1 and 2, and they are made in the same way.

The puzzle, however, is not spherical, but has a surface which is curved along two surface dimensions and has a different radii of curvature along the two surface dimensions. Specifically, the puzzle is made to approximate the shape of the human head and shoulders which is depicted by the puzzle design. As shown in the sectional view of FIG. 13, the base 27 is Styrofoam and is covered with a coating 29 of ferromagnetic filings in a suitable bonding material to make the pieces 26 magne'tically adhere to the base. A wig stand conveniently may be used to provide the base 27.

The invention is not limited to the three-dimensional shapes illustrated, but it also may be in the form of other three-dimensional shapes with compound curves, such as for example, the shape of an egg. The use of different radii of curvature along different surface dimensions makes many unusually attractive puzzle shapes possible. Instead of permanently magnetizing the pieces, the base could be permanently magnetized. The invention considered from a broader aspect could employ means other than magnetic attraction to hold the puzzle pieces on the base such as microhook material. These and many other modifications may be made without departing from the spirit and scope of the invention which is defined in the appended claims.

I claim:

1. A method of making a three-dimensional sheet puzzle comprising providing a three-dimensional form having a surface curved in two dimensions, forming a cover on said surface conforming to the curvature thereof, cutting said cover into pieces sufficiently small so that the pieces can be flattened without appreciable distortion, flattening said pieces, and reproducing the flattened pieces in sheet material which flattens without strain, and depicting on said reproduced pieces a puzzle design which is comprised when said reproduced pieces are fitted together on said base.

2. A method of making a three-dimensional sheet puzzle as recited in claim 1, wherein said puzzle design is depicted on said reproduced pieces after said pieces have been fitted together on said base to cover said base.

3. A method of making a three-dimensional sheet puzzle comprising making a master set of puzzle pieces by the method recited in claim 2 and reproducing said master set of puzzle pieces to reproduce said sheet puzzle. 

1. A method of making a three-dimensional sheet puzzle comprising providing a three-dimensional form having a surface curved in two dimensions, forming a cover on said surface conforming to the curvature thereof, cutting said cover into pieces sufficiently small so that the pieces can be flattened without appreciable distortion, flattening said pieces, and reproducing the flattened pieces in sheet material which flattens without strain, and depicting on said reproduced pieces a puzzle design which is comprised when said reproduced pieces are fitted together on said base.
 2. A method of making a three-dimensional sheet puzzle as recited in claim 1, wherein said puzzle design is depicted on said reproduced pieces after said pieces have been fitted together on said base to cover said base.
 3. A method of making a three-dimensional sheet puzzle comprising making a master set of puzzle pieces by the method recited in claim 2 and reproducing said master set of puzzle pieces to reproduce said sheet puzzle. 